1. Field of the Invention
The present invention relates to telecommunication services and more particularly to a method of locating an idle mobile telecommunication device.
2. Description of Related Art
A general example of an advanced intelligent network (“AIN”) is depicted in FIG. 1 and is designated generally by reference numeral 10. In this figure, circuit-switched pathways (i.e., trunks) that carry voice and data are represented by solid lines, and signaling pathways and other logical connections are represented by dotted lines.
In exemplary network 10, a first station 12 is connected to the public switched telephone network (“PSTN”) 14 via a first service switching point (“SSP”) 16, and a second station 18 is connected to PSTN 14 via a second SSP 20. Stations 12 and 18 may be telephones, fax machines, modems, or other such devices. SSPs 16 and 20 are connected to each other and to a centralized service control point (“SCP”) 22 by a signaling network that may include a first and second signal transfer points (“STP”) 24 and 26. This signaling network carries out-of-band signals that are used to control the switches and to set up and tear down the circuit between the calling party and called party. Currently, Signaling System 7 (“SS7”) is the most commonly used signaling system.
SCP 22 contains control information and call processing logic to assist SSPs 16 and 20 in handling calls. SSP 16 is programmed with logic that defines “trigger points” at which SSP 16 should seek guidance from SCP 22. At these trigger points, SSP 16 sends a query message to SCP 22, and SCP 22 returns a response message to SSP 16. According to SS7, these query and response messages are known as Transaction Capabilities Application Part (“TCAP”) messages.
For example, SSP 16 may include a table that identifies a range of subscriber numbers associated with mobile telecommunication services, and SSP 16 may be programmed with a trigger that causes SSP 16 to query SCP 22 in response to a call origination or termination attempt involving one of those numbers. At that trigger point, SSP 16 would send a TCAP query to SCP 22, providing various parameters such as the calling number and the called number. In turn, SCP 22 would execute service logic to determine what SSP 16 should do with the call, and SCP 22 would then send a TCAP response back to SSP 16. The TCAP response may instruct SSP 16 to route the call to a particular destination or may provide various other instructions or information.
Alternatively, SSP 16 may itself be programmed with logic that indicates how to handle special service calls, without requiring SSP 16 to “dip” into the logic of SCP 22. For instance, in response to a call origination or termination attempt involving a particular number, SSP 16 may execute its own logic to determine what to do with the call. Internal tables and service logic programmed into SSP 16 may then instruct the SSP to route the call via a particular trunk group to a remote destination in the network.
On call origination, once an SSP receives routing instructions from SCP 22 or otherwise determines where in the network to route a call, the SSP may seek to set up a call with a switch serving the terminating location (an SSP or MSC), by engaging in an SS7 signaling session. According to SS7, call setup and tear down between switches is accomplished by a series of messages in the Integrated Services Digital Network User Part (“ISUP”) layer. These messages include the initial address message (“IAM”), the address complete message (“ACM”), the answer message (“ANM”), the release message (“REL”) and the release complete message (“RLC”), among others. The ISUP protocol is defined by ITU-T recommendations Q.761 and Q.764, as well as Bellcore GR-317 CORE and GR-394 CORE, all of which are fully incorporated herein by reference.
To set up a call from station 12 to station 18, SSP 16 first sends an IAM message to SSP 20 via STPs 24 and 26. The IAM message indicates that the originating switch has seized an outgoing circuit, and provides address information (such as the dialed number) and other parameters related to routing and handling of the call. In response, SSP 20 sends an ACM message to SSP 16, to acknowledge that all address signals required for routing the call to the called party have been received and that the call can be connected to station 18. When station 18 goes off hook to answer the call, SSP 20 sends an ANM message back to SSP 16 to signal that station 18 has answered. In response, SSP 16 connects the call to SSP 20, thereby establishing an end-to-end communication path between station 12 and station 18.
The exemplary network 10 illustrated in FIG. 1 can be implemented in both landline and wireless systems. In the landline environment, the network is referred to as an advanced intelligent network (“AIN”). In the wireless environment, the network is referred to as a wireless intelligent network (“WIN”). An example of such a WIN system architecture 30 is shown in FIG. 2. The principal difference is that, in a landline system, station 12 is directly connected to SSP 16, whereas, in a wireless system, station 40 is a mobile station (“MS”) that communicates via radio waves with a base station (“BS”) (not shown) and in turn with SSP (referred to as a mobile switching center 46 (“MSC”)).
With reference to FIG. 2, MSCs 42, 44, 46 are similar, but may perform different functions for a particular MS 40 and for a particular call. For instance, MSC-O 42 is the originating MSC that first receives a call intended for MS 40. From the dialed digits, MSC-O 42 determines that the call should be routed to the home MSC, MSC-H 44, for MS 40. The MSC-H 44 will determine that MS 40 is presently registered with the serving MSC, MSC-S 44.
Another difference between the WIN network 30 of FIG. 2 and the AIN network of FIG. 1 is that a wireless network utilizes a Home Location Register (“HLR”) and a Visitor Location Register (“VLR”), shown as HLR/VLR 48, to manage information such as the profile for the MSC. When the MS registers in a MSC, the MSC sends a REGNOT (Registration Notification) message to the HLR and the HLR will send the profile information for the MS back to the MSC. The MSC will store the information in its VLR (Visitor Location Register). regarding the MS 40, including, respectively, information regarding which MSC is the home MSC, and which MSC is presently serving the MS (“serving MSC” or “MSC-S”). The VLR is updated, for example, whenever a MS registers with the network or is deactivated (powered off). The MSC-S sends an update to the VLR containing the MSC-S's identity (MSC-ID).
In addition, other differences in operation exist between landline and wireless intelligent networks, due largely to differences in industry standards for the two environments. AIN standards are currently embodied in Bellcore's AIN Release 0.1 and AIN Release 0.2, while WIN standards are currently embodied in Telecommunications Industry Association (“TIA”) interim standard IS-771 (which is based on other industry standards, including interim standard IS-41, now known as ANSI/TIA/EIA-41-D, for instance.) Each of these standards is fully incorporated herein by reference.
To set up a call to a MS 40, MSC-O 42 first signals the SCP 22 with TCAP message 60 and response message 62 to determine which MSC is the home MSC corresponding to the mobile identification number (“MIN”, which is related to the NPA-NXX-XXXX of the dialed MS 40), and the call is routed to MSC-H 44 as shown by IAM message 64. Note that the SCP 22 may query the HLR/VLR 48 to determine the identity of MSC-H 44. The MSC-H 44 then sends a location request message 66 (LOC_REQ) to the HLR/VLR 48 to obtain routing information for the serving MSC. If the MS is serviced by the home MSC, ie, the MS is not travelling to another MSC, the HLR will send back a loc_req r.r. message back to the home MSC.
On the other hand, if the MSC is not serviced by the home MSC, but is travelling to another MSC (ie, another serving MSC) upon receiving the LOC_REQ message, the HLR/VLR 48 sends a route request message 68 (ROUTE_REQ) to the MSC-S 46 through the IS-41 network, and the serving MSC, MSC-S 46, responds with a route req r.r. message 70 containing a routing information alias known as a temporary location directory number (“TLDN”), which is passed to the HLR. The MSC-S 46 also creates a record matching the TLDN to the MIN of MS 40. The HLR/VLR 48 then sends the TLDN to the requesting home MSC, MSC-H 44, in a loc_req r.r. response message 72. MSC-H 44 generates an ISUP message 74 to MSC-S 46 using the TLDN. The MSC-S 46 performs a translation of the ISUP and determines that the MS is in the area served by MSC-S 46. The serving MSC sends back to the home MSC an ACM message. The MSC-S 46 then sends a page 76 to the MS 40, and from the MS's response 78, MSC-S 46 obtains the current cell/sector information, described in further detail below. ACM messages 80 and 82 indicate routing is complete, and the call is then established between the MSC-O 42, the MSC-H 44 and the MSC-S 46.
In a typical cellular radio communications system (wireless telecommunications network), an area is divided geographically into a number of cell sites, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS) antenna. The base station antennae in the cells are in turn coupled to a base station controller (BSC), which is then coupled to a telecommunications switch or gateway, such as a mobile switching center (MSC) for instance. The MSC may then be coupled to a telecommunications network such as the PSTN (public switched telephone network) or the Internet.
When a mobile station (MS) (such as a cellular telephone, pager, personal digital assistant (PDA) or appropriately equipped portable computer or computing device, for instance) is positioned in a cell, the MS communicates via an RF air interface with the BTS antenna of the cell. Consequently, a communication path is established between the MS and the telecommunications network, via the air interface, the BTS, the BSC and the MSC.
With the explosive growth in demand for wireless communications, the level of call traffic in most cell sites has increased drastically over recent years. To help manage the call traffic, most cells in a wireless network are usually further divided geographically into a number of sectors, each defined respectively by radiation patterns from directional antenna components of the respective BTS, or by respective BTS antennae. These sectors (which can be visualized ideally as pie pieces) can be referred to as “physical sectors,” since they are physical areas of a cell site. Therefore, at any given instance, an MS in a wireless network will typically be positioned in a given physical sector and will be able to communicate with the telecommunications network via the BTS serving that physical sector.
In addition, both AIN 10 and WIN 30 may include a service node (“SN”) 34, which can provide voice and other interactions with users and can facilitate and perform various enhanced services for the switch. For this purpose, SN 34 may contain programmed service logic, which SN 34 may execute in response to messages received from SSP 16 or MSC 42, 44, 46. In addition, SN 34 may contain an Interactive Voice Response Unit (“IVRU”) or other hardware and software to facilitate interaction with users, such as playing announcements, collecting dual-tone multi-frequency (“DTMF”) digits, and recognizing speech. As shown in FIGS. 1 and 2, a service node such as SN 34 is typically connected to a switch. Consequently, the network may include many service nodes, each programmed to perform the same or similar services for its respective switch.
Exemplary networks 10 and 30 include an intelligent peripheral (“IP”) 36, to which SSP 16 (or MSC 42) and SCP 22 are connected, possibly through one or more STPs. Like SN 34, IP 36 can connect to an AIN call and can be arranged to provide assorted services, including tone generation, voice recognition, playback, compression, call control, recording, and DTMF detection and collection. IP 36 may similarly include an IVRU (not shown) to facilitate various interactions with users. IP 36 can be connected to one or more SSPs and is designed to be application-independent, supporting generic services for more than one application. Unlike SN 34, IP 36 does not have call control logic embedded and must be instructed to perform each operation under the control of SCP 22 using a TCP/IP communication path to SCP 22 and the Bellcore defined SR-3511 ISCP-IP Interface Specification. This standard is fully incorporated herein by reference.
In wireless telecommunication networks, it is not uncommon for a subscriber to misplace or lose their mobile station. In the event that the mobile is lost, there is typically no recourse other than to call the MS in the hopes that someone has found it, answers the call, and informs the subscriber where the MS is located. Newer generations of wireless networks may include mobile positioning centers (“MPC”) and position determining equipment (“PDE”) that can assist in locating a mobile device, but no such assistance is available for legacy networks. What is needed is a method of locating a lost or misplaced MS in legacy networks without the use of an MPC or PDE.